Terminal



. March 26, 1946. N. H. MARTIN TERMINAL ASSEMBLY FOR ELECTRIC CIRCUITSFiled Nov. 6, 1945 Inventor J/. 14. Mum.

A tt orne Patented Mar. 26, 1946 TERMINAL ASSEMBLY FOR ELECTRIC CIRCUITSNorman Hadlow Martin, London, England, as-

signor, by mesne assignments, to International Standard ElectricCorporation, N. Y.', a corporation of'Delaware V 7 Application November6,1943, Serial no. 509,178

In Great Britain December 1, 1942 2 Claims. (Cl. 173 324) The presentinvention relates to terminalassemblies for electric circuits and inparticular to improvements in the construction of such assemblies.

' In electric circuits and apparatus employed in the communication'art,assemblies of large numbers of closely arranged terminals are commonlyused for convenience in wiring and arranging circuits. The necessity forcombining compactness,

flexibility, and cheapness of construction, raises a number of problemsin design and arrangements hitherto used have failed to meet all therequirements in a'completely satisfactory way.

For example, it is well known to mount rows of metal terminal punchingsin holes in strips of insulating material (frequently ebonite or othersimilar rubber product). It is necessary that'theterminals should befixed so that they cannot be easily removed during subsequent assemblyand soldering operations, and to avoid complicated interlockingarrangements involving a lot of different piece-parts, it has beencustomary to fix the terminal punchings by forcing them into (usually)circular holes drilled in the ebonite strips. This requires an elaborateassembly fixture, and close control of the dimensions of the terminalsand holes and is not satisfactory, since the terminals are liable tocome out later on, owing to the softening of the ebonite by heating fromthe soldering iron.

It is the object of the present invention to provide a terminal assemblywhich can employ terminal punchings of the same type as those previouslyused, and in which the difficulties experienced in meeting therequirements are avoided by means of a cheap and flexible arrangement.

According to the invention, there is provided an insulating strip forloosely holding a plurality of electrical terminal punchings, the stripbeing formed so that when a plurality of such strips are piled incontact, each strip locks in position the terminals carried by one ofthe adjacent strips in such manner that they are not removable.

More specifically the invention may comprise an insulating strip forloosely holding electrical terminal punchings, provided with twosubstantially parallel longitudinally extending faces, one of whichfaces has formed thereon along one longitudinal edge a projecting ledgehaving a surface inclined to the said face, the corresponding edge ofthe other face being formed to provide clearance for the said inclinedsurface.

According to another aspect the invention comprises an electricalterminal punching assembly comprising a plurality of similar insulatingstrips piled in contact, each being adapted to hold loosely apluralityof terminal punchings and being so formed that each strip locks inposition the terminals carried by one of the adjacent strips in suchmanner that the are not removable.

The. invention will be explained with reference to the accompanyingdrawing, in which:

Fig. 1 shows; part of the rear elevation of a ter-. minal strip.assembly according to the invention; Fig, 2 shows a side view, partlyinsection, of the assembly of Fig. 1; r r

Fig; 3 shows a-plan view of a terminal strip according to the invention.r c Fig. 4 shows a front elevation of the terminal strip; 'and' Fig. 5shows asection at 3and4.-;;;" 7

Referring to Figs. 1 and'2',-the terminalassembly according to theinvention comprises a base I of any suitable material having on theupper surface a rectangular packing strip 2. Piled on this strip are anynumber of insulating strips. 3 (two only are shown) each carrying anynumber of terminal punchings 4 arranged side by side. The pile issurmounted by a capping strip 5 which may be the same as the strips 3,but will preferably be unprovided with any terminal drillings. The wholeassembly is fixed by a suitable number of screwed rods 6 and nuts (oneonly being shown), which may be secured at the lower ends to a plate 1assembled in a recess or channel in the base i, or they may haveseparate hexagonal or screw-driver heads, or the like.

One of the insulating strips 3 is shown in detail in Figs. 3, 4 and 5.The section seen in Fig. 5 is mainly rectangular. The strip has twoparallel longitudinally extending faces I! and I8, and faces 8 and 9 atright angles thereto. The lower face 8 terminates in a projecting ledgeto which runs longitudinally along the strip, and which has a fiatsurface l9 inclined to theface H,

the lines AA of Figs,

The opposite edge of the strip is chamfered or otherwise reduced at l Iforming a surface roughly parallel to the surface 19, so that when thestrips are piled up as shown in Fig. 2, the chamfer on each stripprovides clearance for the ledge H! of the strip next above. Similarly,if necessary, the packing strip 2 may be chamfered as shown at l2. Itwill be evident that the capping strip 5 need not hav this chamfer.

The strip 3 is provided with a number of circular holes l3, the face 8being recessed with a rectangular slot or key-Way It at the mouth ofeach hole. The diameter of the holes It should preferably be such thatthe thermal punchings 4 can be easily inserted therein without anyforce,

the shoulders l5 of each terminal entering the keyway I 4, thus holdingthe terminal upright and preventing it ,from twisting. it

- It will be seen that when the terminals 4 are inserted in the holes l3in the manner described,

and when the strips are piled up as shown in.

that while the terminals can actually bequite loosely held so that nospecial fixture'is required for putting them in place, they cannot beremoved during any subsequent operatiom,

The holes l6 shown in Figs. 3, 4 and 5 are provided to clear the fixingscrews 6. v Th designpof the strips 3 is adapted for moulding so thatthey maybe manufactured from phenol condensation products and the likein the well known way; These materials are not liableto be appreciablysoftened by the heat of solder- As many strips 3- fitted withterminals-as desired maybe piled'up in the manner indicated, and it canbe easily arranged so: that a given assembly may be added to at anylater time without disturbing seriously the strips already wired. Itwill be noted that the necessary locking of the terminals isaccomplished by the use of only two diiierent piece-parts (3 and 5), andthese can be reduced to one only if another strip 3 is used instead of5. r r

It will be understood that the terminals have been shown in Fig. 2 ashaving difiere-nt lengths. This is purely a matter of convenience; andas regards the present invention, the terminals can have any desiredlengths. Terminals formed with shoulders It: as shown are well known inthe art. 7

Furthermore, the holes I3 are shown cylindrical because this is aconvenient shape tor manufacture. They could however be any; othershape, for example, they could be rectangular slots havingcross-sections sufiiciently large to allow the terminals to be easilyinserted. In such a.case,..the key-ways i4 would not be necessary. Whatis claimed is: 1. In a mountingfor electric terminals, a plurali'ty ofstrips of insulating material, each having two substantially'parallellongitudinally extending faces and a ledge projecting from alongitudinal edge of one face. the corresponding edge of 1 the otheriace being cut away to provide clear- 'anc for the ledge of an adjacentstrip, a hole threughi each of said strips intermediate said faces, saidhole havingan enlarged portion form ing a shoulder; terminal-s withinsaid holes {and projecting from each stripfandremovable there from, ashoulder-on each terminal adapted'to-fit against the shoulder formed bythe enlarged er tion of said hole and" toextend' into the cut-awayportion, and -means' for holding to-getherfsaid strips with the ledg ofeach'overlyingthe'-eut---* away edge of the; adjacen-tstri-pand theshoulf ders'of terminals that stripand obstructing the removal of theterminals therefrom.=- 2". The mounting accordingtoclaim 1-,and inwhich'the shoulder o f each terminaliis atone" side'thereof andtheenlarged portion of the hole through. each strip is shaped to fitsaid, terminal shoulder,. whereby said terminal is held in a} hole 7 orits stripagainst rotation but is free to move longitudinally. r. 5; it vNORMANHADLOW MAI-EH19?

